Process of improving the resistance of soiling of melt spun fibers

ABSTRACT

Polyamide and polyester fibers are rendered highly resistant to soiling by applying to the fibers during the manufacture thereof a finish comprised of a water-soluble lubricating agent, a silicone, and a tin or zirconium compound, and subsequently scouring the fibers to remove substantially all of the lubricating agent while a major portion of the silicone and metal compounds remains adhered to the fiber.

United States Patent Andrew L. Smith Pensacola, Fla. 826,018

May 19, 1969 Nov. 16, 1971 Monsanto Company St. Louis, Mo.

Inventor Appl. No. Filed Patented Assignee US. (I 117/138.8 R, ll7/l38.8 N, 1 17]] 38.8 F, l17/138.8 E, 117/l39.5 CQ, 117/l39.5 CF, 252/86, 252/8.9

Int. Cl D06; 15

Field of Search 117/139.5 CQ,139.5 CF, 138.8 F, 138.8 N; 252/8.6, 8.9;

[56] References Cited UNITED STATES PATENTS 2,747,981 5/1956 Brown et al 117/1 39.50 2,789,956 4/1957 Eder l17/l38.8 N 3,318,659 5/1967 Bullock et a1 8/1 15.6 3,333,983 8/1967 Sellet 117/141 3,348,968 10/1967 Hulbert et al l 17/138.8 FOREIGN PATENTS 746,860 1 111966 Canada OTHER REFERENCES Blumenthal, Zirconium Chemicals, Bleaching and Dyeing Dec. 1950 pp. 81- 83 Primary Examiner-William D. Martin Assistant Examiner-Ralph Husack Attorneys-James H. Barksdale, Jr. and Robert L. Broad, .Ir.

ABSTRACT: Polyamide and polyester fibers are rendered highly resistant to soiling by applying to the fibers during the manufacture thereof a finish comprised of a water-soluble lubricating agent, a silicone, and a tin or zirconium compound, and subsequently scouring the fibers to remove substantially all of the lubricating agent while a major portion of the silicone and metal compounds remains adhered to the fiber.

PROCESS OF IMPROVING THE RESISTANCE OF SOILING OF MELT SPUN FIBERS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to polyamide and polyester fibers and to textile articles produced therefrom which are highly resistant to soiling due to the application of a novel finish composition to the fiber during the manufacture thereof.

2. Description of the Prior Art Soiling of synthetic and natural fibers has always been recognized as a problem by the textile industry. The recent popularity of synthetic fibers for use in carpets and especially for carpets and other textile goods in light or pastel colors has caused the consumer and the industry to become even more aware of the problem. As a consequence, the synthetic fiber industry has attempted to improve the soil resistance of its product by modifying the fiber composition either internally with additives or externally by the application of special finishes.

Polyamide and polyester fibers have found extensive use in textile and carpet goods, and many attempts have been made to increase their resistance to soiling. One of the most promising methods prior to this invention has involved the treatment of finished carpets with dispersions of microparticles such as silica of the oxides of aluminum, titanium, and zirconium. The treatment of finished carpets, however, requires additional processing steps and equipment at the carpet mill, and results in additional expense to the consumer. It would therefore be far more desirable for the fiber producer to treat the fibers during the manufacture thereof, especially if such a treatment could be carried out on existing equipment at minimum additional expense.

SUMMARY OF THE INVENTION According to this invention, polyamide and polyester fibers are rendered soil resistant through a process comprising contacting the fiber with (l) a water-soluble lubricant, preferably being an alkylene oxide derivative selected from the group consisting of polyalkylene glycols and substituted arylpolyloxyethylene) glycols in an amount sufficient to provide on the fiber from about 0.2 to 20 percent of the glycol based on the weight of the fiber, (2A water-soluble salt of zirconium or tin in an amount sufficient to deposit on the fiber from about 0.05 to 1.0 percent of tin or of zirconium measured as an oxide, and (3) A colloidal suspension of a silicone in an amount sufficient to deposit from about 0.1 to 1.0 percent by weight on the fiber It has been found that the combination of certain metal salts and silicones has a definite synergistic effect with respect to improving fiber soil resistance when applied to the fiber with a water-soluble lubricant. Furthermore, the process employed is not only relatively inexpensive and simple, but is readily adaptable to continuous production line manufacture of such fibers.

It is therefore an object of this invention to provide a process for treating polyamide and polyester fibers during the manufacture thereof in order to impart soil resistant properties to textile articles produced from the fibers.

It is a further object of this invention to provide a finish composition which when applied to melt-spun polyamide and polyester fibers facilitates the drawing and processing of these fibers into finished textile articles having exceptional resistance to soiling.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The polyalkylene glycols useful in the practice of this invention are the polyethylene and polypropylene glycols which have a relatively low molecular weight in the range of from about ISO to 2000, are water-soluble, and are liquid at below about 60 C. The polyethylene glycols ranging from triethylene glycol up to PEGl000 molecular weight are particularly preferred.

The substituted arylpoly(oxyethylene) glycols useful for this invention are the type described in detail in US. Pat. No. 3,333,983, where the products are disclosed to be useful as antistatic agents and lubricants for synthetic and natural fibers. In the preparation of these products, an aromatic compound containing at least one phenolic hydroxy group is condensed with from about 9 to 19 moles of ethylene oxide per phenolic hydroxy group to form an aryl phenoxypoly(oxyethylene) glycol. A particularly useful and preferred compound of this type is obtained by reacting one mole of a methyl benzyl phenol with 9 to 15 moles of ethylene oxide.

Other useful lubricants include the alkylene oxide-fatty acid condensates such as those obtained by reacting from 9 to 18 moles of ethylene oxide with one mole of a fatty acid having from 12 to 18 carbon atoms. Here, a particularly preferred compound is PEG 600-monooleate. Also useful are the warm water-soluble alkyl capped polyalkylene glycols of the general formula:

R-O-(CH,-CH,-O),,-CH,-CH,-OH wherein R is an alkyl of 12 to 24 carbon atoms, and n is an integer of from about 9 to 18.

It is contemplated that lubricating agents other than those enumerated may also be used in combination with silicone and tin or zirconium compounds according to the teachings of this invention with good results. This invention is accordingly not intended to be limited to any specific lubricant agents, but may include generally those lubricants which meet the critical requirements of being both water soluble and unreactive with the fiber substrate and the silicone.

The selected lubricating agent is applied to the fiber from an aqueous solution in an amount sufficient to deposit upon the fiber from 0.2 to about 20 percent of the lubricant, based on the weight of the fiber. Sufficient lubricant must be applied to pennit processing of the fiber into yarn and finished textile articles. The optimum amount of any particular lubricant required depends upon the compound selected since the various compounds have different lubricating properties.

In accordance with one embodiment of the present invention, there is added to the fiber in combination with the glycol a water-soluble salt of zirconium and a silicone. Among watersoluble zirconium salts which may be mentioned as useful in the process of the present invention are zirconium acetate, zirconium chloride, zirconium bromide, zirconium oxalate, and zirconium sulfate. The zirconium compound should be added to the fiber in an amount sufficient to provide at least 0.05 percent of zirconium, measured as zirconium dioxide, based on the weight of the fiber. Generally, the zirconium compound is added in an amount sufficient to provide between 0.5 percent and l .0 percent of the zirconium onto the fiber. Amounts greater than 1.0 percent of the zirconium may be added to the fiber, however, the benefits accruing from the application of such additional amounts are not economically warranted.

The silicone or siloxane added to the fiber in combination with the zirconium and glycol is preferably a silsesquioxane having the unit formula RSiO wherein R is a member selected from the group consisting of the methyl, ethyl, vinyl, phenyl, and 3,3,3,-trifluoropropyl radicals. The silicone is generally in the form of a colloidal suspension with a particle size in the range of 10 to 1000A. Materials of this type are described in detail in Canadian Pat. 746,860 where their application to fibers and carpets to impart antislip, dulling, and dry-soiling resistance is discussed.

Although silicones and zirconium compounds have been used in the past to impart soil resistant characteristics to textiles, these compounds are not effective when applied to the fibers as a component of conventional spin finishes normally applied to the fibers during the melt spinning thereof. Even when both the silicone and the zirconium together were added to the conventional finish mixture, there was no appreciable improvement in the soiling characteristics of the carpets ultimately produced from the treated yarn.

It has been found that in order to obtain the benefit of the zirconium and silicone and produce a soil-resistant fiber, it is necessary to replace the conventional water-insoluble finish with a material which is water soluble. Further, it has been found that certain polyalkylene glycols and substituted aryl poly(oxyethylene) glycols can be used with exceptional results.

The conventional finishes referred to herein are typical water-insoluble materials derived from vegetable oils. These oils may be hydrogenated, ethoxylated, or otherwise suitably modified as desired to obtain the required lubricity, solubility, and melting point.

Also, it has been discovered that, although definite improvement in fiber soil resistance can be obtained by the addition of either the zirconium or the silicone to the water-soluble glycol finish, there is an unexpected and surprising synergistic effect produced by the combination of the two additives so that the improvements in soil resistance of the treated fibers is more than 50 percent greater than the sum of the improvements obtained with either additive alone. As a result of this discovery, it is now possible to produce finished carpets with soil resistance far exceeding that obtained by previous methods.

The fibers treated in accordance with this invention are characterized in that they contain on the surface thereof from about 0.2 to percent by weight of the selected water-soluble glycol finish, from about 0.05 to 1.0 percent by weight of a zirconium compound analyzed as zirconium dioxide, and from 0.1 to 1.0 percent by weight of a silicone. Fibers thus treated are processed into the desired textile goods, such as fabrics, sweaters, and carpets by weaving, knitting, and tufting using conventional equipment and procedures. The finished goods are generally subjected to a wet treatment, such as dyeing, bleaching, or scouring before being readied for the ultimate consumer. During this treatment, substantially all of the water-soluble finish is removed from the fiber, while between 60 85 percent of the zirconium and silicone remains tightly adhered to the surface of the fiber. The final fiber product therefore, which demonstrates a remarkably improved resistance to soiling, is characterized only by containing a small amount of zirconium and silicone tightly affixed to the fiber surface. This amount of zirconium remaining is from about 0.03 to 0.85 percent by weight, analyzed as zirconium dioxide, while the amount of silicone remaining is from about 0.06 to 0.85 percent by weight.

Another embodiment of this invention involves the combination of a silicone and a tin salt in the water-soluble glycol finish. Of the several water-soluble tin salts existing, stannic chloride is preferred for its stability and availability. The substitution of the tin salt for the zirconium salt is made without change in the process or levels of finish application.

It is contemplated that the treated fibers containing the selected water-soluble finish and the tin or zirconium and silicone compounds may be dyed or scoured while in a yarn or staple form and before being processed into the final textile end product. In this event, it will be necessary to apply a lubricating finish to the yarn or staple to facilitate further processing. In order to insure that the soil resistant properties imparted to the fibers are not impaired, care should be taken to select a lubricating finish which is water soluble and which can be removed from the final textile product by simple wet treatment.

Fibers useful in the practice of this invention include primarily the polyarnides and polyesters, although other melt spun fibers such as the polyolefins are contemplated. The polyamide fibers, generally known as nylons, are the high molecular weight linear polymers which contain recurring carbonamide groups as an integral part of the main polymer chain separated by at least two carbon atoms. Broadly speaking, nylon polymers are of two general types. One type of nylon is obtainable from polymerizable monoaminomonocarboxylic acids and their amide-forming derivatives, for example ecaprolactam and a-pyrrolidone known generically in their polymerized form as nylon-6 and nylon-4, respectively. The other type of commercial nylon is obtainable from suitable primary or secondary diamines and suitable dicarboxylic acids or amide-forming derivatives thereof. Among thelatter type are polymers formed by the reaction of tetramethylene diamine, pentamethylene diamine, hexamethylene diamine and the like with adipic acid, suberic acid, sebacic acid, and the like. The polymerization product of hexamethylene diamine and adipic acid has the generic name of nylon-66.

The polyesters and copolyesters are those produced by heating one or more glycols of the series HO(CH,),,-OH, where nis an integer of from 2 to 10, with one or more dicarboxylic acids or ester-forming derivatives thereof. Of particular interest is the polyethylene terephthalate fiber which has found widespread commercial acceptance in woven, knitted, and tufted goods.

In order to more fully illustrate the present invention, the following examples are presented. In these examples, carpet samples were blank-dyed by boiling for 60 minutes in a 35:1 liquor to carpet ratio in water containing 0.25 percent of an anionic surfactant detergent. After cooling, the carpet pieces were washed well seven times with deionized water using for each wash about a 20:1 liquor to carpet ratio. The carpet samples were squeezed well by hand after each washing, but par ticularly after the last washing and permitted to dry in the atmosphere for at least 40 hours before the soiling tests were made.

The soiling and cleaning procedure used in performing the tests upon which the examples were based may be described as follows: 2-inch squares of the blank dyed carpets were soiled by tumbling at 60 r.p.m. for one hour with 15 weight percent of synthetic soil in a l-gallon wide mouth jar containing internal baffles to insure adequate mixing. The samples were thereafter cleaned in two steps. ln the first step, the samples were vacuumed with a nozzle attached to a laboratory vacuum line through a length of rubber pressure tubing. The samples were cleaned three times in each direction. All easily removed dirt was taken off in this step. The second step consisted of vacuuming the samples with a hand vacuum cleaner through a half-inch diameter adapter at the end of the cleaner hose. Again, the samples were vacuumed three times in each direction with overlap of the adapter path. The synthetic soil which was used in this soiling test and which is thought to be representative of a cross section of soil across the United States has the following composition:

52.5 percent sifted sawdust 22.3 percent sifted peat moss l0.9 percent calcium carbonate 6.6 percent animal charcoal powder 2.1 percent silica 2.1 percent cement 2.1 percent kaolin clay 1.1 percent mineral oil 0.2 percent furnace black 0.] percent red iron oxide EXAMPLE 1 A commercial nylon 66 carpet yarn having 68 filaments and approximately 1230 total denier was spun with the application of 1.0 percent by weight of a conventional water-insoluble spin finish consisting of 30 percent ethoxylated castor oil and 70 percent of a water-insoluble partially hydrogenated vegetable oil, the finish being applied to the fiber from an aqueous emulsion containing 17 percent solids. The yarn was draw textured using a conventional gear-type texturing head, a drawpin temperature of about l C and a draw ratio of 3.7. The drawn yarns were plied double, prebulked, again plied for a total yarn denier of 4920, tufted into carpets, blank dyed, and evaluated for soiling resistance with the following results:

Original Brightness (OB )-82 Soiled Brightness (SB)35 Brightness Loss (OBSB)47 Brightness Loss, percent59 IOIOIZ 0024 This example illustrates the soiling characteristics of polyamide carpets produced in accordance with the conventional methods and finish compositions of the prior art, where no special additives are used in an attempt to improve soil resistance.

EXAMPLE ii A carpet sample was prepared and evaluated according to the procedure of example 1 except that the improved finish composition of this invention was substituted for the conventional finish of example i Specifically, an aqueous mixture of the following composition was applied to the yarn:

12.0 grams of reaction product of methyl benzyl phenol with 9 molar equivalents ethylene oxide 20.0 grams polyethylene glycol, M. W. 1000 10.0 grams monomethylsilsesquioxane 21.8 grams zirconium acetate solution, 22 percent solids as 3.2 grams hydroxyl amine sulfate 1.2 grams glacial acetate acid The surface of the yarn after drying contained:

1.0 percent of combined ethylene oxide condensate and PEG,

0.3 percent siloxane solids, and

l 120 p.p.m. (parts per million) zirconium.

The finished yarn was draw textured and processed into carpets according to the procedure of example l and evaluated for soiling resistance with the following results:

Original Brightness 80 Soiled Brightness 57 Brightness Loss, percent 28 Comparison with the results obtained in example i show this test sample to have a soiled brightness of 22 units better than the control, and a brightness loss of 27 percentage units better than the control. The advantage of the water-soluble finish, silicone, and zirconium combination over the conventional water-insoluble finish composition is clearly demonstrated.

EXAMPLE ill Two samples were prepared to determine the individual efin the table, W. S. represents water soluble finish consisting of:

6 parts reaction product of methyl benzyl phenol with 9 molar equivalents ethylene oxide and i parts PEG 1000,

Si represents monomethyl silsesquioxane,

Zr represents zirconium,

Percent loss is calculated from the formula: Original-soiled Brightness/Original Brightness, and AB represents difference in soiled brightness between test sample and control.

Comparing the results of example ill with those of example 11, an unexpected and unpredictable synergistic effect between the silicone and the zirconium is clearly evident. if the effect of the zirconium and silicone were merely additive, a AB resulting from the combination would be 6+8 or 14 brightness units improvement over the control. Example ll, however, when compared with the control of example i has a AB of 57-34 or 22 units, an improvement of 50 percent greater than the 14 units which might reasonably be expected.

EXAMPLE IV Finish on yarn Carpet brightness Finish, Si, Zr, Percent Sample percent percent p.p.m. Orig. Soilcd loss Ex. IV 0. 84 0. 42 760 80 30 62 Ex. I 1.0 82 34 59 This data clearly shows that there is no advantage in incorporating the silicone and zirconium with the conventional water-insoluble finish, and that the water-soluble finish is an essential part of this invention.

EXAMPLE V A series of carpet samples were prepared using the same finish ingredients as described in example ll, but at different levels of application. The table below sets forth the various finish compositions and the results of the soil resistance evaluation.

fects of the silicone and the zirconium on fiber soil resistance when applied with the water-soluble finish. The preparation of the samples followed the procedure of example i The finish composition and level of application, and the results of the soiling tests are given below:

' The above data illustrates that uniform and consistently good results are obtained by the method of this invention, and 5, that the levels of silicone and zirconium applied to the fiber may be varied over a reasonable range with no great effect on the end result.

Finish on yarn Carpet brightness W.S., Si, Zr, Percent Sample percent percent p.p.m. Orig. Soiled loss AB Z EXAMPLE VI A commercial nylon 66 carpet yarn having 68 filaments and a total denier of 1230 was melt spun in a conventional manner with the application of an aqueous spin finish of the following composition: A commercial nylon 66 carpet yarn of 68 filaments and 16percent water-soluble finish consisting of 6 parts of reac- 1250 total denier was prepared by draw texturing yarn contion product of methyl benzyl phenol with 9 molar taining a combination finish comprised of PEG-600 monoequivalents ethylene oxide, and parts PEG-1000 oleate and zirconium acetate which was applied to the yarn 2.4 percent zirconium acetate analyzed as zirconium oxide 0 from a single finish bath. The amount of finish applied to the 1.6 percent hydroxyl amine sulfate yarn, and the amount of zirconium remaining on the yarn after 80 percent water the blank dyeing step which effectively removes the water- This spun yarn was draw textured, plied double, and soluble lubricant is shown in the following table for three samprebulked as described in example I. A first portion of this pies: yarn was made into carpet samples without further treatment. 1 5 A second portion of the spun yarn was treated by the applica- Finish appl P t Zr Oz tion of a 1.5 percent aqueous emulsion of monomethylsilifi tfigfi percent z -o sesquioxane, then made into carpet samples for evaluating soil Sample P z dyeing retained resistance.

The table below sets forth the finish compositions, level of 8-2; 8' 3% application, and results of the soiling tests. Data from example 2 5g of 27 6 V is included for purposes of comparison.

Spin finish Y Carpet brightness W.S., Zr, finish, Percent percent p.p.m. Si, percent Orig Soiled loss AB and the silicone, since the improvement obtained with the combination is more than 50 percent greater than might be expected if the effects were merely additive.

EXAMPLE 1X step if desired. Although the re theless appreciable.

EXAMPLE VI] A series of fabric samples were constructed from a commercial polyethylene terephthalate carpet yarn of 60 filaments and 925 total denier. The yarn was prepared by applying two different finish compositions to draw finish-free fiber. The finished yarn was knitted into tapes which were blank dyed and evaluated for soil resistance according to the same procedures previously described for evaluating nylon carpet samples.

The control sample contained 1.06 percent of a water-soluble finish comprised of 10 parts PEG-1000 and 6 parts of the reduction product of methyl benzyl phenol with 9 molar equivalents ethylene oxide.

The test sample contained 1.09 percent of the same watersoluble finish composition, plus 1220 p.p.m. Zr analyzed as zirconium oxide and 2180 p.p.m. of the monomethylsilsesquioxane.

After soiling, the control sample had a brightness of 29.0, while the test sample registered 45.5. The AB of 16.5 units is comparable to the improvement obtained with the nylon carpet samples, and illustrates the finish composition of this invention is applicable to polyester as well as to nylon fibers.

EXAMPLE VH1 suits of the two-stage application are not as good as those obtained from the single application, the improvement over the control sample 1 is never- This data illustrates that a significant portion of the zirconium originally applied to the fiber remains thereon even after the fiber has been subjected to the scouring action of the blank dyeing operation.

it is apparent from the foregoing examples and data given in connection therewith that the process of the present invention provides fibers having significantly improved soil resistance when compared to untreated fibers.

Various changes and modifications may be made in practicing the invention without departing from the spirit and scope thereof, and therefor, the invention should not be limited except as defined in the appended claims.

lclaim:

l. A process of improving the resistance to soiling of melt spun fibers and articles produced therefrom comprising the steps of:

a. applying to the fibers from an aqueous medium from about 0.2 to about 20 percent based on the weight of the fibers, of a water-soluble lubricating agent selected from the group consisting of polyalkylene glycols, substituted arylpoly(oxyethylene) glycols, alkylene oxide-fatty acid condensates, and mixtures thereof, from about 0.1 to about 1.0 percent based on the weight of the fibers, of a silicone being a colloidal suspension of a silsesquioxane having the unit formula:

Three samples were prepared according to the procedure of example 11 using stannic tetrachloride pentahydrate as the metal salt in place of the zirconium. The finish composition RSiO wherein R is selected from the group consisting of methyl, ethyl, vinyl, phenyl, and 3,3,3,-trifluoropropyl radicals, and

This date illustrates that tin may be substituted for zirconium with good results in the practice of this invention. The data further shows that a synergistic effect exists between the tin from about 0.5 to about 1.0 percent, based on the weight of the fibers and measured as an oxide, of a water-soluble salt of a metal selected from the group consisting of zirconium and tin;

b. drying the fibers, and c. Scouring the fibers. 2. A process according to claim 1 wherein the fibers are 

2. A process according to claim 1 wherein the fibers are dried following the application of the lubricating agent and the metal salt and before the silicone is applied thereto.
 3. A process according to claim 1 wherein the fibers are processed into an article prior to scouring. 